Casting machine



March E. A. STEINBOCK ETAL 2,235,443

CASTING MACHINE Filed Dec. 178, 1939 v 2 Sheeis-Sheet 1 IN VEN T 0R5 EoMwvo A. STE/NBOCK -Auaus-r L. WE YH/NG A TTORNEYI.

March 1941- E. A. STEINBOCK ETAL 2,235,443

CASTING MACHINE Filed Dec. 18, 19:9 V 2 Shets-Sheet g EDMUND ASTEINBocn AUGUST L. WEYHING ATTdRNEYl.

Patented Mar. 18, 1 941 PATENT OFFICE- 2,235,443 css'rmo mourns Edmund A. Steinbock and August L. Weyhing, Louisville, Ky.; said Weyhing assignor to said Steinbock S Application December 18, 1939, Serial No. 309,788

9 Claims. (Cl. 22-651) This invention relates to improvements in a castingmachine, .such as is used in the dental industry for making dental castings.

The principal object of the present invention is the provision of a casting machine provided with means which prevents the metal melting flame from engagement with the refractory material of which the mold is formed.

Another object of this invention is the provision of a casting machine which confines the casting metal reducing flame to the confines of the crucible until the nugget of metal is molten, thereby preventing harm to the casting mold as was the condition in the past.

Other objects and advantages of the present invention should be readily understood by reference ,to the following specification when considered in connection with the accompanying drawings and forming part thereof, and it is to be understood that any modifications may be made in the exact structural details therein shown, without departing from or exceeding the spirit of the invention as defined by the appended claims.

In the drawings:

Fig. 1 is a front elevation of one type of a casting machine embodying the improvements of this invention.

Fig. 2 is a rear elevation of certain parts of Fig. 1.

Fig. 3 is an enlarged transverse sectional view, taken on line 33 of Fig. 1.

Fig. 4 is a fragmentary, sectional view through certain of the parts of'Flg. 3, taken on line 4-4 of said Fig. 3.

Fig. 5 isa view similar to Fig. 3, with, however, the parts in a secondsposition.

Fig. 6 is a longitudinal, sectional view through the parts of Fig. 3, taken on line 6-8 of said Fig. 3.

Fig. '7 is a transverse, sectional view taken on line l-| of Fig. 6; and,

Fig. 8 is a view, similar to Fig. 6, but illustrating a modification of the invention.

Throughout the several views of the drawings, similar reference characters are employedvto denote the same or similar parts.

The casting machine illustrated in the draw-.

that the improvements of this invention have equal application to these different kinds and forms of centrifugal casting machines, as well "as to other types of casting machines, and is not to' be limited to the specific form. shown in the drawings.

The machine specifically illustrated in the drawings comprises a base Hi, from which rises a housing formed of a right hand part II and a left hand part l2, secured to one another in any suitable or desirable manner. Near the upper end of the housing HI2, there is provided an aperture for suitable anti-friction bearings in which is mounted ashaft l3. The shaft i3 pro- ,iects through the housing and has secured to its projecting rear end the hub [4 of an arm, to be described in detail later. In operation, the shaft I3 is to be rapidly rotated, together with the arm secured thereto, and to effect this rotation suitable means are enclosed within the housing ll-l2. One such means or mechanism is illustrated in United States Patent No. 1,5 issued on November 17, 1925 to Charles E. Larson and Merrill G. Swenson, and since this driving or rotating mechanism forms no part of the present invention, it' is deemed unnecessary to further illustrate or describe the mechanism. It should be noted, however, that the shaft l3, and its arm, may be more or less rotated, de-. pending upon the size of the casting to be made. For this purpose, the rotating mechanism is provided with a selectable tensioning device, settable through a shaft, rod or the like, indicated by the reference numeral 15. The mechanism, after being set or positioned by the part 15, is tripped by the rod or trigger indicated in th drawings by the reference numeral [6.

The arm hub I4 has projecting from one side thereof the arm i1, and from. the other side the arm I8. The arm. I1 is provided at one end with an upstanding portion is, to which is secured a centering base for the casting mold 2|. The casting mold 2! has its front end in engagement with the inner surface of a plate 22, which is secured, as by screws 23 and 24, to a carriage 25. The carriage 25 is in turn secured, as by a screw 26, to the upper surface of a slide 21 mounted on the upper surface of the arm ii.

In order to slidably-secure the slide 21 on the arm '11, see Figs. 6 and 7, the said slide has depending from it, at opposite sides, arms 28 and 29, which are connected to one another, below the arm II, by cap plates 30 and 3|. The cap plate 3] has depending from ita boss or lug 32, in

which is secured one end of a rod 33. The rod 33 extends from the boss 32, through an. aperture 34, in a lug 35, projecting from the arm II. Beyond the lug 35, the rod 33 is bent to provide a finger piece 36. Surrounding the rod 33, between the cap boss 32 and arm lug 35, is a coil spring 31, abutting on one end with said cap boss 32, and on the other end with the arm lug 35.

As will be seen in Figs. 3, 5 and 7, the carriage '25 is U-shaped in cross section, and its arms 38 and 36 are respectively provided, near their upper ends, with aligned seats 46 and 4| for supporting a crucible 42. The crucible 42, as seen in Fig. 6, is dished, and, at its forward end, is provided witha'funnel shaped discharge 43 having its discharge opening 44 of substantially the same diameter and in alignment with an aperture 45 in the plate 22. Interposed between the crucible opening 44 and. the plate aperture 45 is a bafile, shutter, or the like 46.

The baffle or shutter 46, as seen in Figs. 3 and 7, is so arranged with respect to the plate and carriage 25 as to rest on the upper surface ofthe carriage arms 38 and 36. The battle or shutter 46 is provided with an enlarged end 41 and a reduced handle or tail 48. which, when in the normal position of Figs. 3 and 7, projects considerably beyond the plate 22. The attachment of the baffle or shutter 46 to the plate 22 is by means of a pivot screw 49. The baiile or shutter 46, as will later be made clear, is adapted to be actuated from the position of Figs. 3 and 7 to the position of Fig. 5, and in order that no interference be offered by the pivot screw, the screw 46 is surrounded by a short sleeve 50, on which the pivoting movement of the shutter 46 actually takes place, since the screw 49 is screwed home to clamp the sleeve 50 between its head 49 and the face of the plate 22 without impinging on the'bailie or shutter Mi.-

As seen in Fig. 6, the casting mold 2| comprises a metallic ring 5| filled with a refractory material 52, known in the trade as an investment and composed chiefiy of plaster and silica, and small percentages of other ingredients, all as is well known pression in the upper end of the mold. -This depression 55 is in alignment with the aperture 45 in the plate 22, and the discharge opening 44 of the crucible 42. In order'to allow for the dissi-' pation and escape of the air in the cavity 53, when the casting material is discharged thereinto, the cavity 53 has extending therefrom an air vent 56. i

As is well known, a wax model of the dental casting, or other casting. is first made, which is then invested or surrounded with investment material 52, within the ring 5|. This assembly is then placed in a suitable furnace to melt out the wax model and provide the cavity 53, sprue hole 54 and air vent 55. The resulting mold 2| is then ready for the casting machine. The fin- .ger piece 36, of the rod 33, is then grasped and operated toward the left, as seen in Fig. 2, to draw the slide 21, and'parts carried thereby, including the carriage 26, plate 22 and bafile or trigger 46, from the centering support 26. The mold 2| is then placed on the support 26, at approximately the center thereof, and the rod 33 released, thereby allowing the spring 31' to expand and actuate the slide 21, and parts carried thereby, toward the mold 2| and bring the plate 22 into alignment with the upper or forward end of the mold 2|. The force of the spring 41, through the plate 22, yieldably urges the mold 2| against the base 20, which. due to its angular face, centralizes the mold 2| thereon.

A nugget of metal is then placed within the crucible 42 and a. blow torch, indicated in Fig. 1 by the reference numeral 51, brought to bear on the nugget for melting same to a state of fluidity.

The metal used for making dental castings, in some instances, is a gold alloy, while in other instances is a chromium alloy. Chromium alloys have, in recent years, become more popular and are becoming wider used. The melting point of chromium alloy, as used today, is around 1800" F., which is considerably in excess of the melting point of the gold alloys heretofore employed.

Prior to this invention, and the use of the baffie, or shutter 41, the flame from the blow torch 51 would be directed, after striking the metal nugget through the crucible opening 44 and aligned plate opening 45, against the mold; This flame, in developing the heat necessary for melting chromium alloys, would melt the investment material, both around the sprue hole 54 and the walls of the cavity 53, resulting in a cavity which had a shape other than the necessary and desired shape. The result was a casting which did not match the original wax pattern, or the cavity from which the wax pattern was made. In order to prevent the blow torch flame from attacking the mold, the baiile or shutter 46 is interposed between the crucible discharge opening 44 and the plate opening 45, and confining same to the crucible.

When the metal nugget within the crucible is reduced to a casting state. or a state of fluidity, \the tail 46 of the baflie or shutter 46 is comtacted, and the shutter actuated in a clockwise direction about its pivot 36, and the crucible 42 moved or shoved forward against the plate 22. The trip lever-or trigger i6 is then released to set in operation the arm |l--|8 rotating mechanism, thereby throwing the metal from crucible 43 through the now aligned crucible discharge opening 44 andplate aperture 45 into the mold cav ity 55, and through the sprue hole 44 into the cavity 53. The arm continues to rotate under its own momentum until'the metal in the cavity 53 cools and congeals.

From the foregoing, it will now be appreciated that the mold cavity 53 is kept in its desired shape and condition, and that the resulting casting will conform in all particulars to the size and shape of the cavity 53.

In order to balance the parts carried by the arm H, the arm I8 is provided, at its outer, end, with an upstanding post 56, to which is secured one end of a screw 59 having thereon an adjustable weight 66. The weight 66 is locked in adjusted positions by means of a thumb nut 6|. This balancing mechanism forms no part of the present invention, and is disclosed in the above noted a from a slide rod 61.

standing lugs 62 and 63 on the carriage 25, having aligned apertures therein in which is respectively secured the opposite ends of the rod or bar 64. Surrounding the rod 64 is a coiled spring 65 having one end abutting against the lug 62, and having its other end abutting an arm 66 depending The slide rod 61 projects beyond the carriage 25 where it is provided with a second arm 68, having a pin 69 therein projectingtoward and engaging the crucible 42. It will be appreciated that the spring 65, being under tension, will, upon actuation of the battle or shutter 46, immediately shift the crucible 42 to-its inner, final position.

In order to prevent the inadvertent removal of the crucible 42' from its carriage seat 40-4 I when the baflle or shutter is actuated, the outer end of said crucible may be provided with a small recess or depression 10 receiving the inner end of thepin 69. This connection of the inner end ,of pin 69 with the recess or depression 10 will act as a latch for holding. the crucible in its seat and supplement the weight of the metal in the crucible in retaining same in position.

What is claimed is:

I. In a casting machine, the combination of a refractory mold, a crucible, said crucible and mold respectively having a discharge opening and an intake opening in alignment with one another, said crucible being adapted to have a flame directed thereinto, and pivotally mounted means between the crucible and mold openings preventing communication therebetween during thejtime the flame is being directed into the crucible.

2. In a casting machine of the class described, the combination with a mold having a cavity therein and a sprue hole extending therefrom, and a crucible having a discharge opening in alignment with the mold sprue hole, of a pivotally mounted baflle between the crucible discharge opening and the mold sprue hole.

3. In a casting machine of the class described, the combination of a mold formed of refractory material and provided with a cavity and sprue hole extending therefrom, a carriage adjacent the mold, a crucible on the carriage'and having a discharge opening in alignment with the mold sprue hole, and a pivotally mounted shutter for closing the discharge end of the crucible during the melting of a metal nugget in the crucible.

4. In a casting machine, the combination of a refractory mold having a cavity therein and a sprue hole extending therefrom, a carriage adiacent the mold, a supporting plate on the carriage contacting the mold and having an aper re in alignment with the sprue hole, a crucible on the carriage and having a discharge opening in alignment with the opening in the plate and sprue hole, and a pivotally mounted shutter carried by the plate for closing the discharge opening of the crucible during the melting of a metal nugget therein.

5. In a casting machine, the combination of a refractory mold having a cavity therein and a sprue hole extending therefrom, a carriage adja-- cent the mold, a supporting plate on the carriage contacting the mold and having an aperture in alignment with the sprue hole, a crucible on the carriage and having a discharge opening in alignment with the opening in the plate and sprue hole, a pivotally mounted shutter carried by the plate for closing the discharge opening of the crucible during the melting of a metal nugget therein, and means for shifting the crucible into engagement with the plate upon removal of the closure means.

6. In a' casting machine, the combination of a refractory mold having a cavity therein and a sprue hole extending therefrom, a carriage adjacent the mold, a supporting plate on the carriage contacting the mold and having an aperture in alignment with the sprue hole, a crucible on the carriage and having a discharge-opening in alignment with the opening in the plate and sprue hole, a pivotally mounted shutter carried by the plate for closing the discharge opening of the crucible during the melting of a metal nugget therein, and yieldable means for shifting the crucible relative to the carriage into engagement with the plate upon removal of the baflle.

7. In a centrifugal casting machine, the combination of a revolvable arm, means on said arm for supporting a refractory mold which has a cavity therein and a-sprue hole, said supporting means including a plate having an aperture in alignment with the sprue hole, a crucible having a discharge opening in alignment with the plate aperture and mold sprue hole, and a bafile pivotallymounted on the plate for normally closing communication between the aligned crucible discharge opening, plate opening and sprue hole during the melting of the metal nugget in the crucible and movable to establish communication through these openings after the metal nugget has been reduced to a state of fluidity.

8. In a centrifugal casting machine, the combination of a revolvable arm, means on said armfor supporting a refractory mold which has a cavity therein and a 'sprue hole, said supporting means including a plate having an aperture in alignment with the sprue hole, a crucible having a discharge opening in alignment with the plate aperture and mold sprue hole, a baiiie pivotally mounted on the plate for normally closing communication between the aligned crucible discharge opening, plate opening and sprue hole during the melting of the metal nugget in the crucible and movable to establish communication through these openings after the metal nugget has been reduced to a state of fluidity, and means for shifting the crucible, platev and mold into contactingengagement with one another to take up the space occupied by the baille upon removal of the baflle. I

9. In a centrifugal casting machine, the combination of a. revolvable arm, means on said arm for supporting a refractory mold which has a cavity therein and a sprue hole, said supporting means including a plate having an aperture in alignment with the sprue hole, a crucible having a discharge opening in alignment with the plate aperture and mold sprue hole, a baflle pivotally mounted on the plate for normally closing communication between the aligned crucible discharge opening, plate opening and sprue hole during the melting of the metal nugget in the crucible and movable to establish communication through these. openings after the metal nugget has been reduced to a state of fluidity, and means for shifting the crucible, plate and mold into contacting engagement with one another to take up the space occupied bythe baflle upon removal of the baffle, including a slide rod, a pin on said slide rod and contacting one of the e gaging parts, and a spring for shifting the slide 0d; 

